I am using B&R Community Edtition in some Active Directorys, all is working fine including Backing Up the Backup Server itself.

Now I am using the Software with a customer without an AD. B&R fails backing up the local host at rescan with "15.05.2019 12:10:25 :: Unable to install backup agent: cannot connect to localhost Error: Der Benutzername oder das Kennwort ist falsch." (username/passwort wrong).

I have created a Physical Group "Servers" and put localhost inside. Pressing "Test Credentials" says everything is ok, Connection Okay. But the rescan still fails.
I have disabled all firewall and uninstalled the installed Agent. It reinstalls by clicking on "Apply" at group management.

Have you tried specifying the IP address instead of the localhost entry? Also, if you want to protect the backup server itself, why not to use a standalone Veeam Agent which acts independently from the Veeam B&R server?

The reason was that they simply dont have enough time to take Care of my question. There is no promised Service for Community Users. Thats OK for me, but In would be very Happy to find a solution for this simple Problem.

Got it! Without logs investigation and R&D team involvement it is hard to troubleshoot it via forums, so opening a case later might end up in the support queue. BTW, do you see the same issue on another machine without AD by any chance?

Got it! Without logs investigation and R&D team involvement it is hard to troubleshoot it via forums, so opening a case later might end up in the support queue. BTW, do you see the same issue on another machine without AD by any chance?

Yes, you can export Veeam B&R logs via this wizard and try to locate the error message which happened at the time you started a job. Additionally, try reproducing the same issue on another machine to check if this is a machine-specific error or not.

We don't have a domain in this deployment. I was using a local User (not the original Administrator user) who belonged to the local "Administrators" group and since Veeam B&R Server tries to loop back to access localhost via network, that local user doesn't have Administrator rights when accessing remotely - even if it's localhost.

The solution is to use the local Administrator user, or disable "UAC remote restrictions" as described in the article above.